1. Field of the Invention
The present invention relates to a semiconductor integrated circuit device for reading and writing and for amplifying and outputting data recorded on a record medium comprising a floppy disk which is read by a magnetic head and for recording data on the record medium by flowing current based on written data to a write/read coil of the magnetic head.
The present invention particularly relates to a semiconductor integrated circuit device for reading and writing used in a floppy disk drive device capable of reading and writing to and from both of a floppy disk (lower level record medium) having a storage capacity of, for example, 1 M, 1.44 M, 1.6 M or 2 M and a floppy disk (high capacity record medium) having a storage capacity of, for example, 100 M or more as record media.
2. Description of the Prior Art
A floppy disk drive device capable of reading and writing to and from a floppy disk (hereinafter, referred to as lower level record medium) having a storage capacity of 1 M, 1.6 M or 2 M, is generally known.
In recent years, a floppy disk (hereinafter, referred to as high capacity record medium) having a considerably enhanced storage capacity, for example, a storage capacity of 100 M or 200 M, has been proposed.
A high capacity record medium having an outer shape quite the same as that of a lower level record medium, that is, 3.5 inch size, has been proposed.
Accordingly, an investigation has been started on whether a high capacity record medium may be read or written by a floppy disk drive device the same as that for a lower level record medium.
In view of such a situation, the inventors have investigated on a semiconductor integrated circuit device for reading and writing which amplifies and outputs data recorded on a record medium comprising a floppy disk which is read by a magnetic head and recording data on the record medium by flowing current based on written data to a write/read coil of the magnetic head, particularly on whether a single semiconductor integrated circuit device for both of a high capacity record medium and a lower level record medium can be constructed.
That is, as shown in FIG. 13, a single semiconductor integrated circuit device 100 is installed with read amplifiers 110 through 113 and write drivers 114 through 117 of both media.
In FIG. 13, numerals 101 and 102 designate write/read coils of a write/read head in a high capacity magnetic head for reading and writing to and from a high capacity record medium (hereinafter, referred to as high capacity write/read coil). The high capacity write/read coil 101 is for the surface of the high capacity record medium and the high capacity write/read coil 102 is for the rear face of the high capacity record medium.
Numerals 103 and 104 designate write/read coils of a write/read head in a lower level magnetic head for writing and reading to and from a lower level record medium (hereinafter, referred to as lower level write/read coil). The lower level write/read coil 103 is for the surface of a lower level record medium and the lower level write/read coil 104 is for the rear face of the lower level record medium.
Numeral 105 designates a center tap terminal installed on the semiconductor integrated circuit device 100 for outputting a center tap voltage VCT and the center tap terminal 105 is connected to center taps CT of the high capacity write/read coils 101 and 102 and the lower level write/read coils 103 and 104.
Notations 106X and 106Y designate high capacity input/output terminals H0X and H0Y installed on the semiconductor integrated circuit device 100 to which the high capacity write/read coil 101 is connected. Notations 107X and 107Y designate high capacity input/output terminals H1X and H1Y installed on the semiconductor integrated circuit device 100 to which the high capacity write/read coil 102 is connected. Notations 108X and 108Y designate lower level input/output terminals H2X and H2Y installed on the semiconductor integrated circuit device 100 to which the lower level write/read coil 103 is connected. Notations 109X and 109Y designate lower level input/output terminals H3X and H3Y installed on the semiconductor integrated circuit device 100 to which the lower level write/read coil 104 is connected.
Numeral 110 designates a high capacity read amplifier input nodes of which are connected to the high capacity input/output terminals 106X and 106Y, numeral 111 designates a high capacity read amplifier input nodes of which are connected to the high capacity input/output terminals 107X and 107Y, numeral 112 designates a lower level read amplifier input nodes of which are connected to the lower level input/out terminals 108X and 108Y, numeral 113 designates a lower level read amplifier input nodes of which are connected to the lower level input/output terminals 109X and 109Y, numeral 114 designates a high capacity write driver output nodes of which are connected to the high capacity input/output terminals 106X and 106Y, numeral 115 designates a high capacity write driver output nodes of which are connected to the high capacity input/output terminals 107X and 107Y, numeral 116 designates a lower level write driver output nodes of which are connected to the lower level input/output terminals 108X and 108Y, and numeral 117 designates a lower level write driver output nodes of which are connected to the lower level input/output terminals 109X and 109Y.
Further, the high capacity read amplifiers 110 and 111 as well as the lower level read amplifiers 112 and 113 are integrated to the same semiconductor integrated circuit device and therefore, as shown in FIG. 14, the high capacity read amplifiers 110 and 111 and the lower level read amplifiers 112 and 113 are provided with the same circuit structure such that they can be constructed by the same fabrication process.
In FIG. 14, numeral 118 designates potential nodes for internal power source to which internal voltage Vc is applied, numeral 119 designates an input node to which a corresponding one of the input/output terminals 106X through 109X is connected, numeral 120 designates an input node to which a corresponding one of the input/output terminals 106Y through 109Y is connected and numerals 121 and 122 designate output nodes.
Numeral 123 designates an NPN type bipolar transistor the base electrode of which is connected to the input node 119, the collector electrode of which is connected to the output node 121 and the emitter electrode of which is connected to a common connection point 124, and numeral 125 designates an NPN type bipolar transistor the base electrode of which is connected to the input node 120, the collector electrode of which is connected to the output node 122 and the emitter electrode of which is connected to the common connection point 124 and which constitutes a differential pair of transistors along with the transistor 123. Numeral 126 designates a load element comprising a resistor element connected between the potential node 118 for internal power source and the output node 121 and numeral 127 designates a load element comprising a resistor element connected between the potential node 118 for internal power source and the output node 122.
Numeral 128 designates a constant current source connected between the common connection point 124 and the ground potential node. When a read/write signal R/W is received and the read/write signal R/W signifies writing, the constant current source 128 brings the common connection point 128 into an electrically floating state by which the read amplifier is brought into a deactivated state. Further, when the read/write signal R/W signifies reading, the constant current source 128 performs an operation of drawing constant current from the common connection point 124 to the ground potential node by which the read amplifier is brought into an activated state.
Meanwhile, the high capacity write drivers 114 and 115 as well as the lower level write drivers 116 and 117 are integrated to the same semiconductor integrated circuit device and therefore, as shown in FIG. 15, the high capacity write drivers 114 and 115 and the lower level write drivers 116 and 117 are constructed by the same circuit structure such that they can be constructed by the same fabrication process.
In FIG. 15, numeral 129 designates an output node to which a corresponding one of the input/output terminals 106X through 109X is connected, numeral 130 designates an output node to which a corresponding one of the input/output terminals 106Y through 109Y is connected, numeral 131 designates an input node to which an internal write signal int.WD is inputted and numeral 132 designates an input node to which an internal write signal int./WD that is an inverted signal of the internal write signal int.WD is inputted.
Numeral 133 designates an NPN type bipolar transistor the base electrode of which is connected to the input node 131, the collector electrode of which is connected to the output node 129 and the emitter electrode of which is connected to a common connection point 134 and numeral 135 designates an NPN type bipolar transistor the base electrode of which is connected to the input node 132, the collector electrode of which is connected to the output node 130 and the emitter electrode of which is connected to the common connection point 134 and which constitutes a differential pair of transistors along with the transistor 133.
Numeral 136 designates a constant current source connected between the common connection point 134 and the ground potential node. When the read/write signal R/W is received and the read/write signal R/W signifies reading, the constant current source 136 brings the common connection point 134 into an electrically floating state by which the write driver is brought into a deactivated state. Further, when the read/write signal R/W signifies writing, the constant current source 136 performs an operation of drawing constant current from the common connection point 134 to the ground potential node by which the write driver is brought into an activated state.
Further, a constant current value of the constant current sources in the write drivers 114 and 115 connected to the high capacity input/output terminals 106X and 106Y, and 107X and 107Y, is 5 through 6 times as much as a constant current value of the constant current sources in the write drivers 116 and 117 connected to the lower level input/output terminals 108X and 108Y, and 109X and 109Y.